The invention relates to two-axled vehicles such as scooters.
The weight of traffic means that there is a need for an environmentally friendly alternative to or addition to automotive transport. There is a growing demand for an individual means of transport which can be used above all to move quickly and flexibly and which has to be sufficiently compact that it can be carried in public transport, in the car and indoors. The bicycle is not an adequate solution, since it cannot be carried in public transport. The chain drive mechanism means that fold-up bicycles are still too large and too heavy for most children and older people.
An alternative is the familiar scooter, comprising a frame having a platform section, connected at the front to a steering column in which a front wheel is arranged on a steering rod, and provided at the rear with a back wheel. While one foot is on the platform section, the other foot is used to push the scooter onwards. The absence of chain, gears, cranks, pedals and saddle makes the scooter much lighter and less expensive than the (folding) bicycle. However, a drawback which is common to this known scooter and the bicycle is that the turning circle is limited to a diameter of 3 to 4 m at some speed, since only the front wheel can be turned.
Foot-propelled vehicles are known in which the back wheel is designed so that it can be turned, so that the back of the vehicle can also turn. Kinslow (1949), U.S. Pat. No. 2,474,946 and Rademacher (1969), U.S. Pat. No. 3,442,528, describe 4-wheeled vehicles, of which the front and back wheel axles are rotatably connected to the ends of the platform board by means of non-vertical axles. The two extra wheels, situated at a relatively great distance from one another, make these vehicles wider and heavier compared to the known scooter. They also have the common, significant drawback that the two outer wheels turn relatively far outwards when cornering and will project with respect to the platform section, with the result that both vehicles become significantly wider and there is a high risk of them colliding with the pushing foot and hooking behind or hitting something, especially in situations where a rapid, short turn is required in order to be able to avoid something. Yet another drawback is that the two turning devices of both vehicles proposed cannot be controlled independently of one another. A further ergonomic drawback is that the inner wheels, when cornering, turn inwards, with the result that the space available for the foot is limited and positioning the foot is impossible or extremely critical.
Boyden U.S. Pat. Nos. 3,203,706 and 3,023,022 describes, inter alia, a wide, four-wheeled vehicle, in which the wheels are positioned on wide axles beneath the platform board, in such a manner that they can turn inwards obliquely (at an angle of 60-70 degrees with respect to the road) and to a very limited extent (approx. 10 degrees out of the neutral position) with respect to the platform board. Consequently, the board has to be made extremely high, in order to ensure that when cornering the wheels do not run into the bottom of the board, with resultant instability while, at the same time, the turnability is not greatly increased. Boyden also describes a combined use on ice and snow.
There are also patents which proposed vehicles with a platform board and ordinary handlebars, having one front wheel and one back wheel, of which the back wheel can be turned separately. For example, Vaverek (1969), U.S. Pat. No. 3,620,547 describes a variant of a scooter which can be used and is intended for down hill, driven by the force of gravity. The vehicle has an ordinary steerable front wheel and a back wheel which turns automatically when the frame is tilted, specifically in the same direction as the tilting, as a result of the turning axis being directed obliquely downwards and backwards, so that the virtual intersection between the axis and the ground lies in front of the point of contact between the back wheel and the ground. On account of the direction and position of the axis with respect to the back wheel, this design has the drawback that starting to turn to the left using the ordinary handlebars, which will always subconsciously involve the body, handlebars and frame being tilted slightly to the left (as in a bicycle), according to Vaverek also leads to the back wheel turning towards the left, while to go left it is required and expected that the back wheel will turn to the right. Another drawback of the Vaverek design is that the platform board, which is intended for both feet to be placed on (in order to simulate vedeln when skiing), is situated beneath the frame, with the result that when starting up the foot cannot be placed on the center of the platform. The foot which has been positioned off-center causes lateral loads on the frame, leading to undesirable and/or unexpected turning of the back wheel and therefore to unstable situations. Consequently, it is unsuitable for scooter travel on the ordinary road.
Others have also proposed vehicle designs with one or more turnable back wheels, mostly for the purpose of simulating skiing, but they have the common drawback that, on account of the turning device for the back wheel, they are usually longer than the ordinary scooter, with the result that greater spans are required in order to offer sufficient strength. Consequently, they have to be of relatively heavy design, with the result that the vehicles as a whole do not satisfy the conditions imposed in the context of the problem of compactness and light carrying weight in combination with an improved maneuverability.
NL 1 007 245 reflects the closest state of the art.
The main object of this invention is to provide an individual means of transport which can be used to move quickly and flexibly and which is sufficiently compact that it can be carried in public transport, in the car and indoors.
A further object is to provide a scooter-type vehicle which offers entirely new opportunities for sport activity.
Other objects will become clear from the further description.
With respect to a vehicle of the prior art type, the present invention has a back section or tailpiece that projects as far as behind the back wheel area. The axis is directed forwards with respect to the support surface or ground. The back wheel axle is situated in front of the pivot axis, as seen in the direction of travel.
The shaped part preferably has two supporting arms (referred to below as xe2x80x9cthe two-pronged forkxe2x80x9d), between which preferably a single back wheel with a wide, dimensionally stable running surface is supported via the wheel axle. To reduce the rolling resistance, the running surface is preferably concave, so that instead of a physical line of contact with the road there remains an imaginary line of contact, namely between the two contact points. However, a shaped part which has a single supporting arm with a wheel axle fitting through it is also possible, in which case a wheel (to be referred to below as the xe2x80x9cback wheelxe2x80x9d) is fitted onto this axle on either side of the arm, in order to create the same preferred contact line characteristic.
The above-mentioned suspension of the back wheel axle firstly makes the back wheel self-righting, so that it will seek to run straight on under the influence of a vertical load in the vertical position of the scooter. The wheel stabilizes itself and cannot wobble. Secondly, if the frame is tilted slightly out of the purely vertical position, the shaped part together with the back wheel will turn outwards the other way, so that a bend is steered into even though the front wheel, which is operated by traditional handlebars, just remains facing straight ahead. The bend is in the same direction as that in which the scooter is tilted out of its vertical position. The result is extremely great maneuverability which can be enhanced still further by also steering the front wheel.
The entire principle of the invention is suitable for being of very short, low and narrow design. Stability is enhanced by a low-lying centre of gravity, which is achieved in a design in which the platform section runs obliquely forwards and downwards in a direction which intersects the front wheel in the vicinity of the location where it is in contact with the supporting surface, while at least a part of the frame is at a lower level than the highest point of the back wheel.
To allow the low frame to tilt to its maximum extent, the lowest point of the platform section is also the narrowest part, while the highest section, just above the back wheel, is the widest part.
Preferably, the scooter is furthermore designed in such a manner that the frame, at least in the region in front of where the shaped part is attached to the tailpiece, comprises two parts which are at a horizontal distance from one another, and that the shaped part has the front corners of its top surface located between and at a certain distance from the said frame parts, so that the said frame parts limit the angle of deflection of the shaped part together with the back wheel. This limitation of the angle of deflection is a safety measure which is taken because otherwise the combination of relatively high speeds and very sharply taken bends could give rise to a risk of the back wheel xe2x80x9cescapingxe2x80x9d.
The frame is made rigid and strong by connecting the frame tubes to one another in front of and behind the platform section using a transverse element, for example by welding a strip of metal between them. The advantage of this is that as a result the vehicle transmits steering tilting movements xe2x80x9cone by onexe2x80x9d to the back wheel, but also that as a result the back wheel reacts very directly to changes in pressure passed on via the feet, which may be brought about as a result of changes in the body posture and movement. However, the rigidity is detrimental to the ride comfort. However, this can be made resilient again by simple means as a result of a relatively thin plate of flat but flexible material, for example 6 mm triplex, being prestressed across the two said transverse connections, with the result that the plate adopts a convex position and during riding the centre part of the footplate cannot bend sufficiently far to reach the tubes. Good shock absorbing can be achieved by arranging an overlapping layer of rubber between transverse connection and plate, so that the plate material is supported on the rubber. The prestressing is easy to achieve by welding the two connecting strips between/on the tubes not in a flat position, but rather at an angle of, for example, 40 degrees with respect to one another, i.e. each facing upwards towards one another at an angle of approximately 20 degrees with respect to the tube.
To increase the number of degrees of freedom in movement and the number of driving techniques, a large number of use adjustments are possible. For example, the scooter may be designed in such a way that front fork and shaped part are provided with a plurality of holes for the front axle and back axle, respectively. In this way, it is possible to move the wheels, so that the length of the pivot arm of the back wheel or the steering characteristics are altered.
The vehicle according to the invention offers a number of completely new possible uses which cannot be achieved with a bicycle or a traditional scooter, nor with other sports equipment, such as skateboards. It is possible to gain speed by executing defined movements using the scooter. One of these becomes possible if the back wheel in its shaped part is pulled towards its central position by a spring.
The vehicle is designed so that it can be folded together or folded up, in a similar way to a folding bicycle, if it is designed in such a way that the front wheel of the frame is attached with respect to a steering tube of the steering column by means of a hinge pin which is perpendicular to the longitudinal central plane of the frame in the xe2x80x9cstraight-onxe2x80x9d position of the front wheel.
A design of high strength and stability which can still be folded up is obtained if the steering tube is composed of a fixed steering tube assembly, which bears the hinge pin for connection of the frame and inside which a fork rod can be displaced in rotation but not in the axial direction, and a slideable steering tube assembly, which can slide in the axial direction and rotate about the fork rod and is hingedly connected to the frame by means of a stabilizing element, which can itself execute hinged movements with respect to the slideable steering tube assembly. Given suitable dimensions, the scooter which has almost been folded up can be carried over the shoulder.
A new, interesting possibility for maneuvering and also for increasing speed, for example, by movements executed using the arms are obtained in a design in which the unit comprising the front wheel of the frame, the steering column, the fixed steering tube assembly, the slideable steering tube assembly and the stabilizing rod is dimensioned in such a way that the steering column is both statically and dynamically adjustable between a limit inclined-forwards position and an arbitrary inclined-backwards position.
It is also possible for the slideable steering tube assembly to be designed in such a way that the steering column can only be dynamically adjusted, specifically in such a manner that, starting from a limited, furthest forwards position, the column can only be pulled backwards under a rising spring stress. The advantage of this design is that the position in which it slopes furthest backwards is also clearly limited. This point can be optimally selected by means of design measures so that the center of gravity of the body, which will move backwards as a result of the change in the angular position of the steering column, will never lie beyond the back wheel. This means that the mobility of the steering column can be maximized while also ensuring stability of the body.
It is still possible to travel with a fixed, sloping-forwards position of the steering column, so that the wheel base is shortened, providing the scooter with a different driving performance, but it is also possible to use the handlebars to execute a pump-action movement as a combination of inclining the steering column forwards and backwards and tilting the scooter towards both sides. This is once again a hitherto unknown possible movement for a vehicle, with which bodily energy can be converted into speed.
It is advantageously also possible to use the handlebars to steer in the opposite direction to a bend which is launched into by tilting left and right, resulting in a slalom-like movement and also converting bodily energy into speed.
The conversion of energy into speed can be promoted by scale. Larger wheel sizes allow the pivot arm of both the front wheel axle and the back wheel axle to be oversized with respect to their respective pivot pins (i.e. the distance in cm between the wheel axle and the pivot pin), while the short distance from the platform part to the road is nevertheless maintained. The advantage of this is that the wheel deflections of both front and back wheel can become much greater and that it is therefore possible to make more effective use of energy feedback from cornering, resulting in a vehicle which can increasingly be kept at speed more by means of the weight and power of the body, and therefore needs to be pushed by foot only when it is being started.
Many traditional scooters are provided with a brake which acts on the back wheel and can be operated using a heel at a location at the end of the platform section of the scooter. In the scooter according to the invention, the braking aspect is preferably resolved in such a way that a brake is arranged on the shaped part of the back wheel. In this way, the brake remains active in all pivot positions of the back wheel.
In this case, the brake is preferably operated not from the platform section, since in that area, with a view to achieving a compact structure of the entire vehicle, there will be space for a bit more than one footxe2x80x94the standing footxe2x80x94while the pushing foot, when it is not actively pushing, can also be supported on the tailpiece. Therefore, it is advantageous if the brake is formed by a lever which projects behind the tailpiece, where it can be operated, and on which lever there is a brake block, so that the latter comes to bear against the running surface as a result of actuation.
A lever of this type which projects behind the tailpiece as part of the brake can, for example if the scooter is used to drive off a kerb, grind along the road. To prevent this, the solution is proposed that that part which projects behind the tailpiece bears a wheel with a rotation axle which is perpendicular to the central longitudinal plane of the scooter. To operate the brake, the wheel is simply pressed downwards, and the wheel makes it possible to drive off a kerb or similar elevated structure without problems.
There are also various interesting possibilities relating to the steering.
For example, an improved posture can be achieved if the steering rod has a part which is bent forwards and on which the handlebars are arranged, and if the handlebars are formed by two parts which run obliquely downwards and backwards with respect to a short center piece, each being of a length which is approximately equal to the width of a hand. Moreover, narrow handlebars contribute to safety and make the scooter lighter and more compact, thus also improving the portability.
Other maneuvering options are achieved if not only the back wheel can pivot in the manner indicated, but if the front wheel together with the front wheel axle is/are supported by a shaped part which can turn with respect to the front part of the frame about an axis which is directed downwards and backwards at an acute angle with respect to the support surface (xe2x80x9cthe roadxe2x80x9d) This can be achieved in two ways. The said axis, which is imaginary, can be physically realized by being formed by a steering column with handlebars. But instead of rotatable handlebars there may be a non-rotatable tilting element for the vehicle, which is rigidly connected to the frame at least in the lateral direction. This tilting element does not have to coincide with the said imaginary axis, but rather may be arranged outside it on the frame.
In that case, there is no longer any need for handlebars for the purpose of influencing the position of the front wheel, since this automatically occurs in the event of lateral tiltingxe2x80x94in the opposite direction, obviously, so that the back wheel and front wheel in combination consistently steer into a clear bendxe2x80x94but the tried-and-trusted handlebars may be retained for the two hands to be placed on, or it is possible just to have a knob which is to be operated by one hand.
The idea of using a turning axis which is directed downwards and backwards at an acute angle with respect to the road for the front wheel xe2x80x9csuspensionxe2x80x9d, as has just been outlined, has been developed as a more detailed embodiment of the basic idea of the invention, as described in claim 1, with the result that the maneuvering options can be extended still further using the same pivoting principle. Surprisingly, however, it has been found that it is also of interest if simply the steering column in the folded-up position, takes an inclined-forward position and the axle of the front wheel is situated behind the center axis of the steering column.
This can be used with a fixed back wheel or with a back wheel which can pivot according to the invention. Although this is at the expense of a dynamic adjustment of the steering column during riding, it does provide a simpler and therefore less expensive vehicle with maneuvering possibilities which have been hitherto unknown.
Conversely it turns out that, while the dynamic adjustability was developed as an elaboration of the basic concept of the invention, this feature in itself is also interesting when applied with a two-axled vehicle which just has fixed front and back wheel axles.
Then, it is preferable once again to use a fork with a single front wheel and a wide running surface or a fork part with a wheel on either side with punctiform contact with the road. The loading in combination with the two wheel contact surfaces with the road has a stabilizing effect on the riding characteristics. A vehicle of this type has the same, albeit reduced, self-aligning effect when the frame is tilted as the vehicle with a pivotable back wheel according to the invention, but has the advantage that the turning of the wheel resulting from tilting of the frame can be influenced by hand using the handlebars.
Furthermore, the handlebars can be made to execute hinged movements as described, with the same advantages. It is thus possible for an ordinary scooter with a fixed back wheel also to be made self-aligning and to make a very small size of scooter much more stable.
To make this design foldable, the invention also provides design options.
However, surprisingly it is also possible, using the same inventive idea, to design the scooter for use on snow, both substantially horizontally and on a slope. This can be achieved if, in the designs described, the wheels are replaced by snowboards or by short skis.
Finally, an embodiment which is designed for use on ice is also possible. In that case, the wheels are replaced by double skates or double blades.
Since the operating techniques are not dependent on pushing off by foot, an embodiment with a motor drive is also conceivable.
The invention will be explained below with reference to the drawings in which like numerals represent like elements throughout the several views.